1. Field of the Invention
The present invention relates to an electrolytic processing method for electrolytically processing the surface of a metallic member, particularly a steel member such as a stainless steel member. More particularly, the invention is concerned with a method which facilitates various electrolytic processing steps such as descaling, polishing, passivity treatment, coloring, plating and so forth to be conducted on a metal surface.
2. Description of the Related Art
Hitherto, mechanical, chemical and electro-chemical techniques have been used for the purpose of conducting various types of processing on the surfaces of metallic products, such as descaling, polishing, passivity treatment, coloring, plating and so forth. These known techniques, however, suffer from the following problems.
For instance, shot-blasting which is a typical example of mechanical descaling techniques is often difficult to conduct due to problems such as generation of dust and noise which seriously impair the working environment. In addition, this technique undesirably allows a work-hardened layer to remain on the surface of the processed product which adversely affects the corrosion resistance and mechanical properties of the product.
Chemical descaling known as pickling or acid cleaning requires a long processing time and encounters difficulty in regard to the disposal of the acidic cleaning solution after use. In recent years, a method has been proposed which makes use of a pickling paste. This method enables efficient pickling of large-sized structural members at the site but still requires an impractically long processing time and tends to cause unevenness in pickling effect.
A typical electro-chemical descaling method is a process known as electrolytic pickling. This technique can considerably shorten the processing time but generally requires a large-sized tank for maintaining a bath in which the object is immersed. The application of this technique is therefore limited.